Research Summary Three-dimensional shape and volume can be sensitive indicators of the physiological state of the cell, and are being extensively studied by biologists from very diverse fields. There are numerous publications relating cell shape to morphogenesis, cancer, toxicity, apoptosis, adhesion, or locomotion. Not only is morphology an indicator of other processes, but it can in turn regulate intracellular signaling. Parameter related to morphology, cell volume, is crucial in osmoregulation and, like morphology, it is thought to supply feedback to cellular function. A number of methods have been proposed to image the surface or measure the volume of individual cells. However a simple microscopic technique to accomplish these goals is lacking. We have previously developed a method for imaging surfaces of transparent objects using either a laser scanning or a conventional microscope equipped only with a digital camera and a bandpass filter. The contrast is generated by adding a concentrated dye to the medium. When applied to solid materials, the method is robust and achieves nanometer vertical resolution with most concentrated dyes;however, its use with biological cells can be hampered by dye toxicity and dye leakage into the cells. We propose to undertake additional research to adapt this method to living cells. Specifically, we plan to demonstrate its usefulness and sensitivity for studies of ion channels and apoptosis. We hope that success of this project will enable biologists to easily image and measure cell morphology and volume using conventional equipment. PUBLIC HEALTH RELEVANCE: Project Narrative Changes in cellular 3D morphology and volume can be sensitive indicators of various physiological processes, such as toxicity, motility or cancerous transformation. While these cellular characteristics are being actively studied by researchers from diverse biomedical fields, there is no simple technique to observe and quantify them with an optical microscope. We propose to develop a method that will enable researchers to apply a conventional optical microscope to obtain detailed information about cell surface and volume.